Patients with chronic inflammatory bowel disease, especially Crohn's disease, often develop decreased zinc levels. This is especially problematic in pediatric patients with Crohn's since zinc deficiency can exacerbate symptoms associated with Crohn's disease including growth stunting, impaired would healing, susceptibility to infections, and gastrointestinal derangements. Many hypotheses have been proposed in prior studies, but not clear etiology has been defined. In our study, we utilized stable isotope techniques to study zinc metabolism in children with Crohn's disease (CD) and matched healthy controls. We hypothesized that children with Crohn's would exhibit lower plasma zinc levels, decreased zinc body pool masses, increased endogenous fecal zinc excretion, and lower fractional zinc absorption than controls. In our study, enrolled subjects are admitted for a six day stay after completing a 14-day zinc adaptation diet (12 mg/d) to complete 24-hour cumulative urine and fecal specimens, as well as daily serum samples, following the administration of 0.5 mg 67Zn (po) and 70Zn (iv). Zinc absorption, endogenous fecal excretion, fractional zinc absorption, and zinc pool masses are calculated from isotope enrichments (determined via mass spectrometry) and cumulative zinc excretion from the samples. At the present time 12 Crohn's patients and 12 controls have been studied, with the remainder of the controls (13), and Crohn's patients (3) to be studied by September 2000. Compartmental models will also be completed on all subjects. Preliminary data sets from the first five subjects with Crohn's disease when compared to the controls showed abnormal zinc metabolism in the children with Crohn's. They exhibited increased endogenous fecal zinc excretion, along with lower plasma zinc absorption.